Cold is the greatest killer in cold water latitudes. The Marine Safety Unit defines "cold water" to mean water where the monthly mean low temperature is normally 59ºF or less. According to the Coast Guard, a temperature of 60ºF was selected because, "a person of average body build, in good health, wearing work clothes and a life preserver could be expected to survive about eight hours”. However, regulations are one thing and real life is another. So for the purposes of this writing we will consider cold water to be anything less than 70ºF.
Remember the first rule of cold water survival is to stay dry. So with this said there are three basic guidelines to follow:
Do not get into the water if you can avoid it.
If you do go into the water get out as soon as possible.
If you can’t get all the way out, get as much of your body out as you can, especially your critical heat loss areas, the head, neck, armpits, sides and groin.
Shelter is the primary key to cold water survival, to be considered sufficient; shelter must offer some sort of thermal protection and flotation.
Clothing
The type of clothing that you wear provides an important component of your “shelter”. The clothing that you wear should be broken down into three layers: Inner, mid, and outer. These three layers work together to trap heat, wick moisture, breathe, block wind, and repel water. You will need this layered protection even if you are wearing an immersion suit. Your head is the source of 50-70 percent of your body’s heat loss making it important to remember to wear a watch cap or hat to cover your head.
Flotation
The only cold water survival device that will provide adequate protection for extended time in cold water is an immersion suit. These anti-exposure suits are ultimately the best wearable cold-water survival devices sold on the market today. However, they do not provide the necessary need for every day floatation protection. Without some form of flotation even strong swimmers will find it difficult to remain afloat in cold water.
Personal Flotation Devices
Crewmen must wear some sort of flotation as a routine component of their personal gear, especially in heavy seas, at night or during dangerous operations. Because there are so many different types and styles available today, it is absurd not to wear something.
Note: It is important to remember that everyone floats differently and just because a PFD works for one person that does not mean it will work correctly for you. Ideally, the PFD should float you face up, feet down; your head should be inclined 20 to 30 degrees back from vertical. The water level on your chest should be no higher than the armpits, preferably lower. You should be able to maintain the HELP position with only occasional swimming strokes. Do not allow yourself to be lulled into a false sense of security just because the device is Coast Guard Approved. Unless you have actually put it on and tested it in the water you will not know if it works properly for you!
